Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 192351
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
651 PM CDT Sun Aug 19 2018

.SHORT TERM...(This evening through Monday)
Issued at 216 PM CDT Sun Aug 19 2018

Upper level low pressure was deepening over the Western High Plains
early this afternoon. This was spreading deeper moisture northward
into the area. A more widespread rainfall will struggle a bit to
move northeast into drier air but most locations should see some
rainfall. Some of the heavier rainfall will be near Interstate 29
this afternoon. As low pressure deepens over northwest MO and
southwest IA tonight the more organized area of rain and
thunderstorms should develop across northwest IA. Right now not
expecting any flash flooding issues as the model soundings hinting
that as the low pressure deepens to the south a stronger northeast
flow in the low levels could advect some of that drier air back into
the region and and keep rainfall rates at a moderate to lower end
heavy rate. Will still need to watch out in these areas though as
the environment does support heavier rainfall and if the drier air
is not as deep then heavier rates will be possible.

During the afternoon a few funnel clouds will be possible with
surface to 3 km CAPE values around 175 J/kg and fairly low LFC
heights. With very weak wind shear any funnels that could touch down
would be very brief and difficult if not impossible to detect on
radar.

The effects of the low pressure will be slow to shift east on Monday
and areas east of Interstate 29 may be a bit wet for the morning.
Clouds will also be a bit slower to exit and will limit afternoon
temperatures. Will have the warmest readings in central SD, the mid
70s, while parts of northwest IA and southwest MN may only reach the
upper 60s.

.LONG TERM...(Monday night through Sunday)
Issued at 216 PM CDT Sun Aug 19 2018

With the exception of Thursday night, Monday night through next
weekend looks to be mostly dry. A fast moving system will swing
through on Thursday and could linger into Friday. It`s a bit far
out to be too concerned but a few severe storms will be possible
so will be a time frame to watch out for. Otherwise looks like a
warming trend through the period with temperatures at or slightly
above normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 644 PM CDT Sun Aug 19 2018

Steady light rain will continue for much of the area through
Monday morning, with isolated embedded thunderstorms also posing a
risk of heavy rainfall and gusty winds. Low cloud decks and
reduced visibility will accompany rain overnight, with improving
cloud and visibility conditions by mid-day Monday after rain moves
to the eastward. East of I-29, isolated thunderstorms will still
be possible through Monday evening. North winds will gust into the
20 to 30 knot range over the next 24 hours.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...VandenBoogart


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